Ravens rookie cornerback Asa Jackson has been suspended four games for a violation of the NFL’s performance enhancing drugs policy, the league announced Tuesday.

The fifth-round pick from Cal Poly will begin his suspension immediately, meaning he will miss the final three games of the regular season and not be eligible for reinstatement until the day following the Ravens’ first potential postseason game.

“We are aware of this matter, but due to the confidentiality of the program, we are unable to provide additional comment on the situation,” the Ravens said in a released statement.

Jackson was inactive for the first 10 games before playing in the Ravens’ last three contests due to injury problems at the cornerback position. He has recorded one special-teams tackle but has yet to see any time as a defensive player.

The Ravens hadn’t announced a corresponding roster move as of Tuesday afternoon.